The present invention relates to a tumbler lock with a supplemental member for locking the rotation of the rotor, of the type comprising a barrel or a rotor turning in a bore of a lock body or a stator, said rotor comprising a longitudinal blind slot provided with an inlet for a key for the introduction of a serrated key, said rotor comprising a plurality of transverse slots passing through and crossing the longitudinal slot in each of which is mounted a tumbler urged outwardly of the rotor by a spring, each tumbler comprising an opening arranged to be traversed by the key whose serrations coact with the edge of said openings, the tumblers being all deflected by the introduction of the serrated key corresponding to the combination of the lock, the bore of the stator comprising a hollow for the reception of each tumbler projecting from the rotor.
Tumbler locks have received considerable development because of their simplicity, implying a low price, associated with good resistance to picking with tools acting on the tumblers.
To improve further the security supplied by such locks, in particular so as to offer a wider range of combinations, the object of the present invention is to provide a tumbler lock comprising a supplemental member for locking the rotation of the rotor, said member being of different structure from the tumblers.
In U.S. Pat. No, 2,083,859, there is disclosed a combination lock whose combination is easily modifiable with the help of a key having two fingers engaging in the lock to act on a coupling element between the button frame and one of the permutation discs. This coupling element is constituted by a ring having a projection engaging in part in a notch provided on a portion of the combination disc and a portion in engagement in a notch of the frame button. An element movable transversely relative to the cylinder permits locking the coupling element in the coupled position, during engagement of the key, to modify the combination, the latter acts on said movable element which slides transversely so as to free said coupling element which is then inactive. This transversely movable element ensures locking of the coupling between the frame button and the permutation disc but does not ensure locking per se of the lock.
Also, and again in the interest of increasing the security offered by such locks, it is of interest to provide a tumbler lock whose combination can be changed by the user so as to offer a greater flexibility of use of this type of lock, in particular by permitting a limitation of access and/or modification of the combination of a lock of this type.
There is known from FR-A-1 384 183, a lock of the type comprising a recess in which is rotatably mounted the barrel to actuate a bolt, several grooves surrounding the barrel and adapted to be transversely adjusted in the recess, these grooves receiving tumblers so as to block the rotation of the barrel and being maintained in engagement with each other, said grooves being adapted to be unlocked from each other so as to permit the tumblers to adapt to the contour of a new key introduced through these tumblers. This lock moreover comprises a tumbler incurring no locking by coaction with the grooves or with the recess but which retains the key and whose particular sliding is ensured by grooves provided in said recess. Moreover, the locking mechanism described in this document to obtain a modifiable combination of the tumblers is relatively complex.
There is known from FR-A-2 396 853, a locking mechanism actuable first by a provisional key and then by a final key. This lock comprises a stator and a rotor disposed in the stator and an assembly of members projecting from the rotor in the stator so as to block the rotation of the rotor in the stator. Certain members are maintained, by a locking pin, in a position to free the rotor in the stator whilst others are active. Thus, a provisional key is arranged to act on only these active members. So as to pass into the final key position, the locking pin is withdrawn, which frees the members which were thus far inactive. An intermediate plate playing no active role in the freeing of the rotor relative to the stator is also freed by withdrawal of the locking pin and is positioned to play a protective role, in particular by masking the access to the opening through which was engaged the locking pin.
This lock arrangement has the drawback that its combination can be modified only once by operating on a portion of its fittings.
In these locks, it is necessary to modify the combination of the tumblers to modify the combination of the lock. Thus, another object of the invention is to provide a lock with tumblers provided with a supplemental locking member whose combination is easily changeable.